L'inférence RDFS dans Iéna en utilisant ARQ (SPARQL)

Question

Les documents Jena ici https://jena.apache.org/documentation/javadoc/jena/index.html indiquent que createOntologyModel inclut un raisonneur faible pour la fermeture transitive sur les hiérarchies de sous-classe et de sous-propriété, ce qui est tout ce que je recherche. A partir d'un modèle simple:

x:A rdf:type rdfs:Class . 
x:A x:prop1 x:whatever . 

x:B rdf:type rdfs:Class . 
x:B rdfs:subClassOf x:A . 
x:B x:prop2 x:other . 

x:myInstance rdf:type x:B . 

Je cherche à interroger pour rdf:type x:B et obtenir toutes les propriétés pour B et A superclasse, par exemple

(?all = <x:whatever>) (?props = <x:prop1>) -> (?type = <x:A>) -> [Root] 
(?all = <x:A>) (?props = <rdfs:subClassOf>) -> (?type = <x:B>) -> [Root] 
(?all = <x:other>) (?props = <x:prop2>) -> (?type = <x:B>) -> [Root] 
(?all = <rdfs:Class>) (?props = <rdf:type>) -> (?type = <x:B>) -> [Root] 

J'ai expérimenté avec cet exemple pour un peu. Il compile et s'exécute, mais ne donne que les propriétés de B et ne marche pas sur l'arbre subClassOf. Je crois que j'ai manqué un paramètre de base ou l'utilisation du schéma RDF qui permet au raisonneur de faire son truc. Des indices?

public class jena2 { 
    private static void addRaw(OntModel m, String s, String p, String o) { 
    m.add(ResourceFactory.createStatement(
      new ResourceImpl(s),new PropertyImpl(p),new ResourceImpl(o)) 
     ); 
    } 

    public static void main(String[] args) { 
    OntModel model = ModelFactory.createOntologyModel(); 

    addRaw(model, "x:A", "rdf:type", "rdfs:Class"); 
    addRaw(model, "x:A", "x:prop1", "x:whatever"); 
    addRaw(model, "x:B", "rdf:type", "rdfs:Class"); 
    addRaw(model, "x:B", "x:prop2", "x:other"); 
    addRaw(model, "x:B", "rdfs:subClassOf", "x:A"); 
    addRaw(model, "x:widget", "rdf:type", "x:B"); 

    StringBuffer sb = new StringBuffer(); 

    sb.append("PREFIX x: <x:>"); 
    sb.append("PREFIX rdf: <rdf:>"); 
    sb.append("PREFIX rdfs: <rdfs:>"); 
    sb.append("SELECT *"); 
    sb.append("WHERE {"); 
    sb.append(" x:widget rdf:type ?type ."); 
    sb.append(" ?type ?props ?all ."); 
    sb.append("}"); 

    Query query = QueryFactory.create(sb.toString()); 
    try (QueryExecution qexec = QueryExecutionFactory.create(query, model)) { 
     ResultSet results = qexec.execSelect() ; 
     for (; results.hasNext() ;) { 
      QuerySolution soln = results.nextSolution() ; 
      System.out.println(soln); 
     } 
     } catch(Exception e) { 
     System.out.println("epic fail: " + e); 
    } 

} 

Answer 1

(ceci est pas une réponse complète)

Comme par commentaire ci-dessus, un code de travail:

import org.apache.jena.ontology.OntModel; 
import org.apache.jena.query.*; 
import org.apache.jena.rdf.model.*; 
import org.apache.jena.vocabulary.RDF; 
import org.apache.jena.vocabulary.RDFS; 

public class jena2 { 

    private static void addRaw(OntModel m, Resource s, Property p, Resource o) { 
     m.add(ResourceFactory.createStatement(s, p, o)); 
    } 

    public static void main(String[] args) { 
     OntModel model = ModelFactory.createOntologyModel(); 

     Resource A = ResourceFactory.createResource("x:A"); 
     Resource B = ResourceFactory.createResource("x:B"); 
     Property prop1 = ResourceFactory.createProperty("x:prop1"); 
     Property prop2 = ResourceFactory.createProperty("x:prop2"); 
     Resource whatever = ResourceFactory.createResource("x:whatever"); 
     Resource other = ResourceFactory.createResource("x:other"); 
     Resource widget = ResourceFactory.createResource("x:widget"); 

     addRaw(model, A, RDF.type, RDFS.Class); 
     addRaw(model, A, prop1, whatever); 
     addRaw(model, B, RDF.type, RDFS.Class); 
     addRaw(model, B, prop2, other); 
     addRaw(model, B, RDFS.subClassOf, A); 
     addRaw(model, widget, RDF.type, B); 

     StringBuffer sb = new StringBuffer(); 

     sb.append("PREFIX x: <x:>"); 
     sb.append("PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>"); 
     sb.append("SELECT * {"); 
     sb.append(" x:widget rdf:type ?type ."); 
     sb.append(" ?type ?props ?all ."); 
     sb.append("}"); 

     Query query = QueryFactory.create(sb.toString()); 
     try (QueryExecution qexec = QueryExecutionFactory.create(query, model)) { 
      ResultSet results = qexec.execSelect(); 
      for (; results.hasNext();) { 
       QuerySolution soln = results.nextSolution(); 
       System.out.println(soln); 
      } 
     } catch (Exception e) { 
      System.out.println("epic fail: " + e); 
     } 

    } 
} 

Sortie:

(?all = <x:A>) (?props = rdfs:subClassOf) -> (?type = <x:B>) -> [Root] 
(?all = <x:other>) (?props = <x:prop2>) -> (?type = <x:B>) -> [Root] 
(?all = rdfs:Class) (?props = rdf:type) -> (?type = <x:B>) -> [Root] 
(?all = <x:B>) (?props = rdfs:subClassOf) -> (?type = <x:B>) -> [Root] 
(?all = rdfs:Resource) (?props = rdfs:subClassOf) -> (?type = <x:B>) -> [Root] 
(?all = rdfs:Resource) (?props = rdf:type) -> (?type = <x:B>) -> [Root] 
(?all = rdfs:Class) (?props = rdf:type) -> (?type = rdfs:Resource) -> [Root] 
(?all = rdfs:Resource) (?props = rdfs:subClassOf) -> (?type = rdfs:Resource) -> [Root] 
(?all = rdfs:Resource) (?props = rdf:type) -> (?type = rdfs:Resource) -> [Root] 
(?all = rdfs:Resource) (?props = rdfs:subClassOf) -> (?type = <x:A>) -> [Root] 
(?all = <x:whatever>) (?props = <x:prop1>) -> (?type = <x:A>) -> [Root] 
(?all = rdfs:Class) (?props = rdf:type) -> (?type = <x:A>) -> [Root] 
(?all = <x:A>) (?props = rdfs:subClassOf) -> (?type = <x:A>) -> [Root] 
(?all = rdfs:Resource) (?props = rdf:type) -> (?type = <x:A>) -> [Root] 

Il a également des rendements les propriétés de la classe RDFS A